6/usr.bin/bsdiff/bspatch/bspatch.c

   1 /*-
   2  * Copyright 2003-2005 Colin Percival
   3  * All rights reserved
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted providing that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  16  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
  18  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  22  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  23  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  24  * POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <bzlib.h>
  31 #include <stdlib.h>
  32 #include <stdio.h>
  33 #include <string.h>
  34 #include <err.h>
  35 #include <unistd.h>
  36 #include <fcntl.h>
  37
  38 static off_t offtin(u_char *buf)
  39 {
  40         off_t y;
  41
  42         y=buf[7]&0x7F;
  43         y=y*256;y+=buf[6];
  44         y=y*256;y+=buf[5];
  45         y=y*256;y+=buf[4];
  46         y=y*256;y+=buf[3];
  47         y=y*256;y+=buf[2];
  48         y=y*256;y+=buf[1];
  49         y=y*256;y+=buf[0];
  50
  51         if(buf[7]&0x80) y=-y;
  52
  53         return y;
  54 }
  55
  56 int main(int argc,char * argv[])
  57 {
  58         FILE * f, * cpf, * dpf, * epf;
  59         BZFILE * cpfbz2, * dpfbz2, * epfbz2;
  60         int cbz2err, dbz2err, ebz2err;
  61         int fd;
  62         ssize_t oldsize,newsize;
  63         ssize_t bzctrllen,bzdatalen;
  64         u_char header[32],buf[8];
  65         u_char *old, *new;
  66         off_t oldpos,newpos;
  67         off_t ctrl[3];
  68         off_t lenread;
  69         off_t i;
  70
  71         if(argc!=4) errx(1,"usage: %s oldfile newfile patchfile\n",argv[0]);
  72
  73         /* Open patch file */
  74         if ((f = fopen(argv[3], "r")) == NULL)
  75                 err(1, "fopen(%s)", argv[3]);
  76
  77         /*
  78         File format:
  79                 0       8       "BSDIFF40"
  80                 8       8       X
  81                 16      8       Y
  82                 24      8       sizeof(newfile)
  83                 32      X       bzip2(control block)
  84                 32+X    Y       bzip2(diff block)
  85                 32+X+Y  ???     bzip2(extra block)
  86         with control block a set of triples (x,y,z) meaning "add x bytes
  87         from oldfile to x bytes from the diff block; copy y bytes from the
  88         extra block; seek forwards in oldfile by z bytes".
  89         */
  90
  91         /* Read header */
  92         if (fread(header, 1, 32, f) < 32) {
  93                 if (feof(f))
  94                         errx(1, "Corrupt patch\n");
  95                 err(1, "fread(%s)", argv[3]);
  96         }
  97
  98         /* Check for appropriate magic */
  99         if (memcmp(header, "BSDIFF40", 8) != 0)
 100                 errx(1, "Corrupt patch\n");
 101
 102         /* Read lengths from header */
 103         bzctrllen=offtin(header+8);
 104         bzdatalen=offtin(header+16);
 105         newsize=offtin(header+24);
 106         if((bzctrllen<0) || (bzdatalen<0) || (newsize<0))
 107                 errx(1,"Corrupt patch\n");
 108
 109         /* Close patch file and re-open it via libbzip2 at the right places */
 110         if (fclose(f))
 111                 err(1, "fclose(%s)", argv[3]);
 112         if ((cpf = fopen(argv[3], "r")) == NULL)
 113                 err(1, "fopen(%s)", argv[3]);
 114         if (fseeko(cpf, 32, SEEK_SET))
 115                 err(1, "fseeko(%s, %lld)", argv[3],
 116                     (long long)32);
 117         if ((cpfbz2 = BZ2_bzReadOpen(&cbz2err, cpf, 0, 0, NULL, 0)) == NULL)
 118                 errx(1, "BZ2_bzReadOpen, bz2err = %d", cbz2err);
 119         if ((dpf = fopen(argv[3], "r")) == NULL)
 120                 err(1, "fopen(%s)", argv[3]);
 121         if (fseeko(dpf, 32 + bzctrllen, SEEK_SET))
 122                 err(1, "fseeko(%s, %lld)", argv[3],
 123                     (long long)(32 + bzctrllen));
 124         if ((dpfbz2 = BZ2_bzReadOpen(&dbz2err, dpf, 0, 0, NULL, 0)) == NULL)
 125                 errx(1, "BZ2_bzReadOpen, bz2err = %d", dbz2err);
 126         if ((epf = fopen(argv[3], "r")) == NULL)
 127                 err(1, "fopen(%s)", argv[3]);
 128         if (fseeko(epf, 32 + bzctrllen + bzdatalen, SEEK_SET))
 129                 err(1, "fseeko(%s, %lld)", argv[3],
 130                     (long long)(32 + bzctrllen + bzdatalen));
 131         if ((epfbz2 = BZ2_bzReadOpen(&ebz2err, epf, 0, 0, NULL, 0)) == NULL)
 132                 errx(1, "BZ2_bzReadOpen, bz2err = %d", ebz2err);
 133
 134         if(((fd=open(argv[1],O_RDONLY,0))<0) ||
 135                 ((oldsize=lseek(fd,0,SEEK_END))==-1) ||
 136                 ((old=malloc(oldsize+1))==NULL) ||
 137                 (lseek(fd,0,SEEK_SET)!=0) ||
 138                 (read(fd,old,oldsize)!=oldsize) ||
 139                 (close(fd)==-1)) err(1,"%s",argv[1]);
 140         if((new=malloc(newsize+1))==NULL) err(1,NULL);
 141
 142         oldpos=0;newpos=0;
 143         while(newpos<newsize) {
 144                 /* Read control data */
 145                 for(i=0;i<=2;i++) {
 146                         lenread = BZ2_bzRead(&cbz2err, cpfbz2, buf, 8);
 147                         if ((lenread < 8) || ((cbz2err != BZ_OK) &&
 148                             (cbz2err != BZ_STREAM_END)))
 149                                 errx(1, "Corrupt patch\n");
 150                         ctrl[i]=offtin(buf);
 151                 };
 152
 153                 /* Sanity-check */
 154                 if(newpos+ctrl[0]>newsize)
 155                         errx(1,"Corrupt patch\n");
 156
 157                 /* Read diff string */
 158                 lenread = BZ2_bzRead(&dbz2err, dpfbz2, new + newpos, ctrl[0]);
 159                 if ((lenread < ctrl[0]) ||
 160                     ((dbz2err != BZ_OK) && (dbz2err != BZ_STREAM_END)))
 161                         errx(1, "Corrupt patch\n");
 162
 163                 /* Add old data to diff string */
 164                 for(i=0;i<ctrl[0];i++)
 165                         if((oldpos+i>=0) && (oldpos+i<oldsize))
 166                                 new[newpos+i]+=old[oldpos+i];
 167
 168                 /* Adjust pointers */
 169                 newpos+=ctrl[0];
 170                 oldpos+=ctrl[0];
 171
 172                 /* Sanity-check */
 173                 if(newpos+ctrl[1]>newsize)
 174                         errx(1,"Corrupt patch\n");
 175
 176                 /* Read extra string */
 177                 lenread = BZ2_bzRead(&ebz2err, epfbz2, new + newpos, ctrl[1]);
 178                 if ((lenread < ctrl[1]) ||
 179                     ((ebz2err != BZ_OK) && (ebz2err != BZ_STREAM_END)))
 180                         errx(1, "Corrupt patch\n");
 181
 182                 /* Adjust pointers */
 183                 newpos+=ctrl[1];
 184                 oldpos+=ctrl[2];
 185         };
 186
 187         /* Clean up the bzip2 reads */
 188         BZ2_bzReadClose(&cbz2err, cpfbz2);
 189         BZ2_bzReadClose(&dbz2err, dpfbz2);
 190         BZ2_bzReadClose(&ebz2err, epfbz2);
 191         if (fclose(cpf) || fclose(dpf) || fclose(epf))
 192                 err(1, "fclose(%s)", argv[3]);
 193
 194         /* Write the new file */
 195         if(((fd=open(argv[2],O_CREAT|O_TRUNC|O_WRONLY,0666))<0) ||
 196                 (write(fd,new,newsize)!=newsize) || (close(fd)==-1))
 197                 err(1,"%s",argv[2]);
 198
 199         free(new);
 200         free(old);
 201
 202         return 0;
 203 }